(a) Technical Field of the Invention
This invention generally relates to a shoe in which an orthopedic adjustment has been integrated into the construction of the shoe itself. More specifically, the invention entails; adjusting one or more of the soles or other construction features of the shoe itself in order to accommodate a medical condition or treatment regimen.
The shoe substrate has a direct impact on the knee and ankle joints. A knee joint has three compartments—an inner, medial femorotibial compartment; an outer, lateral femorotibial compartment; and a frontal, anterior femoropatellar compartment. A normal knee joint has collateral ligaments that strap together the medial and lateral sides of the joint and cruciate ligaments that provide crossing within the joint. Together, these ligaments stabilize and strengthen the knee.
Within the knee joint there are two types of joint cartilage: fibrous cartilage (the meniscus) and hyaline cartilage. Cartilage is a thin, elastic tissue that protects the bone and makes certain that the joint surfaces can slide easily over each other ensuring smooth painless knee movement. The meniscus has tensile strength and can resist pressure essentially acting as a shock absorber. The hyaline cartilage covers the surface along which the joints move. In addition, the joint is lubricated by a fluid produced by the synovial membrane. The meniscus serves to distribute the load of the body evenly, and also aids in disbursing this synovial fluid for joint lubrication.
There are two primary ways in which the knee joint may lose its normal functionality—traumatic injury or age related degeneration. Consequently, depending on the degree of a traumatic injury and what part of the knee was injured, the injury itself may lead to post traumatic degeneration. In either case the cartilage inevitably will wear over time and has a very limited capacity for self-restoration. Any newly formed tissue will generally consist of a fibrous cartilage of a lesser quality than the original hyaline cartilage. As a result, new cracks and tears will continue to form in the cartilage progressively causing inflammation and a loss of lubrication from reduced or lost synovial fluid. In turn this then leads to varying degrees of knee pain that is proportional to the degree of degeneration.
Among the more common traumatic knee injuries that lead to degeneration of the knee joint would be a meniscal tear, an anterior cruciate ligament (“ACL”) tear, or an intra-articular bone fracture. The first two are often seen in sports related injuries. The intra-articular bone fracture conversely is usually seen in hard falls and motor vehicle accidents. In this type of injury, the break crosses through and negatively affects the smooth surfaces of the involved articulating cartilage.
As joint degeneration progresses, so comes the development of osteoarthritis. This in essence is caused by the general wear and tear of the joint. As the hyaline cartilage and the meniscus break down and wear away, this causes the bones to rub together, causing pain, swelling, and stiffness. Bony spurs or extra bones may also form around the joint, and the ligaments and muscles around the knee become weaker.
The biomechanical aspects of gait and impact alignment have been medically recognized. It is well-known and well documented that improved alignment and altering the dynamic forces on the relevant compartment in the knees can significantly alleviate the symptoms, reduce and slow disease progression, and in some cases, allow the joint to heal to some degree. In this respect, well-known biomechanical and clinical studies have established the usefulness of a lateral wedge in reducing the load on the medial knee compartment.
The present invention is generally directed at various uses and positions of a wedge angle to alleviate symptoms of pain at the knee joints, especially knee pain associated with degenerative joint disease, to slow the progression of degenerative joint disease in the knee, and to help prevent premature degeneration of the knee joints in susceptible persons. The wedge angle is integrated into the design of the shoe's sole, thereby not interfering with the normal functionality, safety, fit, or comfort of a shoe. This contrasts with the majority of current practice and prior-art devices wherein adjustments to shoes are made to only portions of the sole, or by a double taper, or by means of an insert, an external attachment, or other devices worn by a user in addition to the shoe.
In this invention primarily, it is the shoe sole construction and design itself that is being modified to accommodate some orthopedic goal which has been medically prescribed. In this sense, the shoe would be custom-made to accommodate the orthopedic condition being treated, accommodated, or prevented. However, stating that this shoe would be custom-made, does not mean that it would be custom-made for each individual and or further adjusted in a trial and error fashion like a great many of the prior-art. Rather, it would be custom-made in its unique and novel fabrication and design, but would be universal in its application for all persons regardless of their individual symptoms and degree of their orthopedic condition.
(b) Description of the Relevant Art
A considerable number of patents relate generally to adjusting a shoe to accommodate a medical condition by the wearer. Many of these inventions take the form of an insert, or external device added or attached to the shoe, and some feature integrated adjustments.
In U.S. Pat. No. 6,205,685 B1, Kellerman discloses an adjustable orthotic insole to be used for therapeutic adjustment, and which is customized to the user. The Kellerman insole can be modified by the user such as to adjust elevated areas within the orthotic insert and relieve areas of pressure on the foot, much like an orthotic insert. By trial and error placement of pads of varying thicknesses on the bottom surface, the user can create a customized therapeutic device capable of relieving pain and stress. The trial and error method of adding and removing pads appears to be the primary essence of the invention. The Kellerman specification does state that expert alignment can be provided by a doctor adjusting the pads to correct particular misalignments or problems with the feet.
Kellerman states that an infinite number of adjustment features can be included and that the custom shape of his invention can be a permanently prescribed orthotic, or it can be a temporary device used until a permanent orthotic is fabricated. The Kellerman device begins with a base insert comprised of a non-compressible sheet of flexible but deformable material in the range of 10 to 100 mils in thickness. Vinyl resin, polyethylene and polypropylene are all identified as optimum materials for the base. The base material is attached to the inside of the shoe in a variety of ways, including the use of Velcro and other commercial loop materials.
U.S. Pat. No. 5,138,774 by Sarkosi is similar to the Kellerman invention in many respects. However, Sarkosi attempts to set forth an adjustable shoe insole for providing therapeutic relief by including an assortment of thin, removable, stackable support pads. In essence, the user is enabled to stack a series of small pads onto various regions of the insole in order to build up support in particular areas as required for greater comfort. Sarkosi states that by choosing specific materials set forth in the patent, and constructing the pads to be thin, the result is an insole that is non-skid such that it stays appropriately in place when stacked. The adjustable pads are not sewed or glued together, and additional pads may be added, and pads removed over time, as needed. In this sense, the Sarkosi invention is essentially the use of inserts comprised of thin, stackable comfort pads in a shoe insole.
U.S. Pat. No. 4,841,648 by Shaffer, et al. is directed to a personalized insole kit for a shoe. The basic idea behind this patent is to develop an insole kit comprised of a collection of specific foot regions, each of which can be modified for a specific therapeutic effect. The thrust of this patent is also directed to a shoe insole kit that can be modified and adjusted by the end-user consumer. The summary section states that the Shaffer article is a personalized insole self-made by the patient for relief of foot discomfort, including a plurality of corrective components, each having a shape formed for a specific correction. The six primary adjustment regions identified in the application include an arch pad, a heel pad, a metatarsal pad, a lesion pad and others. The various regional components assemble together to form the general outline of the insole. The claims of the patent are all directed to a device defined by a plurality of removable and replaceable corrective components which are to be personalized for comfort by the end-user.
Another patent similar to Shaffer is U.S. Pat. No. 4,633,877 by Pendergast. This patent also sets forth an orthopedic insole component which is to be added to the interior of a shoe for a therapeutic effect. As with Shaffer, Pendergast also divides the insole into specific and discreet regions. All of the Pendergast segments are of the same thickness such that when assembled, the device will be “flat” from side to side and from posterior to anterior. However, although the overall device is of the same thickness, the various segments are constructed such that they are each made from materials having a predetermined range of firmness. Each of the specific regions has its own durometer selected from one of a group of ranges of durometers set forth in the patent. Accordingly, the various insole regions have a different hardness, which can be selected for specific desired therapeutic effect. The Pendergast invention is an insert article as opposed to an integrated shoe sole custom-designed for a particular effect.
U.S. Pat. No. 5,042,175 by Ronen is titled “User-Specific Shoe Sole Coil Spring System and Method”. The Ronen device is a user-specific shoe sole that is customized to the individual to achieve a specific orthopedic goal. The customized shoe sole of Ronen is achieved by a specific coil spring construction. The coil spring system layout and stiffness characteristic may be customized to serve the needs of different users and different applications. A user's weight and particular comfort and/or orthopedic requirements are met by fitting the sole with a greater or lesser quantity of springs with different levels of stiffness. Ronen states that the result is a shock-absorbing distribution pattern that suits the requirement of a particular application. All of the Ronen claims are limited to the coil spring element.
U.S. Pat. No. 4,756,096 by Meyer is directed to a custom-molded insert for footwear, and the patent is more particularly directed to an insert to be used with ski boots. The Meyer insole is a one-piece, thin, contoured blank of semi-rigid, bendable, resilient material molded such as to include the complete detail of the full plantar surface of the foot. As such, the Meyer insole provides a four-point contact with a supporting surface of the footwear at the heel, great toe, and at least two, spaced metatarsal heads. According to the inventor, this arrangement provides natural balance and a proper dynamic positioning of the foot and immediate energy transfer between the foot and the footwear, such as a boot or ski. In essence, the problem Meyer is attempting to address is the fact that looseness, or sloppiness, inside a ski boot can lead to loss of control, or rubbing, or other repetitive stress injuries to the feet. The claims are all limited to a one-piece insert that is constructed such as to mold closely to the foot. Meyer does not address customizing a shoe for a therapeutic effect.
U.S. Pat. No. 5,014,706 by Philipp is titled “Orthotic Insole with Regions of Different Hardness”. With this invention, the title of the patent says it all. As shown in FIGS. 1 through 6 of the patent, regions of the insole may be selected to have different hardnesses by altering the type of material used to comprise that portion of the insole. The regions which are specifically defined in the drawings are selected by the inventor to be those areas in which a particular therapeutic adjustment may be needed for some users. Each of the regions of the insole is constructed of a deformable material, but a particular durometer, or hardness, is assigned to each of the regions as needed. The claims of the patent are all directed to specified regions of differing hardnesses.
U.S. Pat. No. 4,813,157 by Boisvert, et al. is another variation of adjustable shoe insole wherein a plurality of adjustable thickness layers are used to build up certain regions of the insole. Boisvert states that the insole comprises superimposed pad layers made of a flexible material for the top layers and a cork material for the remaining pad layers. This patent states that a pressure adhesive, such as hot-melt glue, could be used to releasably interconnect the superimposed pad layers in order to allow repeated peel-off removal and reconnection of the layers. The patent consists of a single, independent claim and thirteen dependent claims, and the feature of multiple layers of support which may be peeled off and reapplied is a required feature of all of the claims.
U.S. Pat. No. 2,909,854 by Edelstein is an older patent directed to pressure-relieving insoles. As shown in the drawing, Edelstein accomplishes the goal of relieving pressure by having a cut-away portion of the insole. The aperture areas of the insole are used to provide relief, and the inventor specifically notes the relief of calluses by enabling the callused area to extend into the aperture such as to relieve walking pressure on the callus.
U.S. Pat. No. 4,620,376 by Talarico is a patent limited to “forefoot valgus compensation.” Although his shoe sole has a lateral wedge, it is restricted primarily to the forefoot only, and does not encompass the entire span of the lateral side from front to back. It does not incorporate the heel, or the midfoot. Furthermore this invention is a two directional wedge. Although there is a lateral wedge (distal forefoot only), it does not maintain a height and thickness that is substantially the same from front to back on the lateral side. The sole in Talarico's invention is longitudinally beveled downward from back to front whereby the rear of the forefoot compensation is higher than the front of the forefoot compensation. This longitudinal bevel by default will simultaneously cause a progressively decreasing lateral wedge angle moving from the rear of the forefoot compensation to the front of the forefoot compensation. By design his invention is limited in its application to only 5% of the general population with this “foot” deformity, and does not address ailments of the knees.
U.S. Pat. No. 6,725,578 by Kerrigan similar to Talarico provides a laterally wedged shoe sole but goes further to include and compensate not just the forefoot, but also the heel. Although Kerrigan goes further than Talarico to include the heel, this invention is still limited because it also does not encompass a lateral wedge that spans the entire lateral side from front to back, but rather it is wedged only at the heel and forefoot and in a multidirectional fashion. In addition it has a cantilever medial arch support at a raised height on the medial side. By design it does not incorporate or compensate a lateral wedge at the midfoot or toes purposely to attempt to “reduce the peak knee varus torque and hip adductor torque values in early and late stance during walking and running.”
U.S. Pat. No. 4,862,605 by Gardner is an inner sole with a lateral wedge similar to Talarico and Kerrigan but it takes it further to allow the wedge to include the span from the heel to the toes. But like that of Talarico and Kerrigan, it is also a two directional wedge. Although this has a lateral wedge, it too does not maintain a height and thickness that is substantially the same from front to back on the lateral side. The inner sole in this Gardner invention is also longitudinally beveled, tapering downward from heel to the toes, from back to front, whereby the rear of the heel compensation is higher than the front of the toes compensation. This is essentially the same effect as that of a heel lift. In addition, this longitudinal bevel by default will simultaneously cause a progressively decreasing lateral wedge angle moving from back to front. Furthermore it must be noted that the heel area is several degrees lower than the portion running from the heel area longitudinally to the toe area. This is in theory an attempt to present a “condition whereby the calcaneum or heel bone will strike a more natural and uniform plane as the foot starts to pronate, thereby presenting a more stable function of the foot.”
The patents mentioned above, and other prior-art devices, fail to adequately solve the problems associated with painful or arthritic knees. The prior-art devices fall into four broad categories—those that attach an external corrective material to the outsole or bottom of the shoe, those that add an insert inside the shoe, those that might chemically engineer the soles in their fabrication to have a variability of durometry or hardness, and those that wedge only a portion of the sole or have a two directional taper.
In the first category, external corrective materials, wedged or otherwise, that are attached to the outsole or bottom of the shoe are especially wrought with problems. The least of these problems would be that the overall comfort and feel of the shoe would be changed by adding something foreign. More so, any external attachment will also change the height of the shoe sole. This height increase will be directly transferred to the entire leg. If used on only one shoe, this will increase the overall leg length compared to the opposing side. The effect would be that of a leg length discrepancy. The result will be an awkward gait, a pelvic shift, and undue stress or discomfort over time referred to the hip and spine.
In addition, external attachments may not be universal for all types of shoes, meaning they may not fit all shoes and tread patterns. For the shoes they do fit, the degree of fit may vary greatly by the shoe. These can be difficult to apply and in some instances it may require much trial and error, and adjustment by the wearer, or a medical provider. They are not universal to the patient or the degree of arthritis either.
Most importantly however, these external attachments may actually be dangerous for the wearer. Since they are attached to the outside of the shoe, they are not part of the shoe. By raising the height of the shoe from the ground, this changes the center of gravity and stability of the shoe potentially leading to balance issues, falls, and foot, ankle or other injury. Because shoe tread contacts the ground, any attachments to the bottom of a shoe are going to be prone to getting caught on obstacles or uneven walking surfaces during ambulation as well. Furthermore, if the attachment becomes loose, this will increase this risk and or the device may just fall off. Another important danger is that external materials change the traction of the shoe because it will cover all or a portion of the shoe's natural tread. Essentially any external attachment to a shoe is a danger to the wearer for these reasons, and can potentially cause a person to fall leading to serious injury. Most of these external attachments are not custom made to the individual shoes either. By default, given the countless shoes in existence, this makes their compatibility and fit highly variable and primitive at best.
In the second category, those that add an additional insole or insert, wedged or otherwise, inside the shoe, are wrought with problems as well. By default these are additions to existing shoes that are placed on or attached to the native insole inside the shoe instead of to the outsole outside the shoe. Shoe inserts of all types are likely as numerous as there are shoes. Most are very similar and claim to aid in some ailment. These types of orthotics in majority are primarily for foot ailments and rarely for the knee or ankle ailments. Even for any that may have a lateral wedge, it is typically limited to the heel, the wedge does not traverse the span on the lateral side, and the wedge is not at the same thickness front to back. Furthermore, when adding inserts into an existing shoe, this will decrease the inside height and space of the shoe box that is available for the foot. This significantly changes the overall fit and feel of the shoe. Frequently, this will cause the need to loosen the shoe laces to accommodate the loss of foot space. Simultaneously, as these inserts decrease the height inside the shoe, they will increase the overall height of the shoe sole because they are positioned over the shoe's native insole. This height increase will be directly transferred to the entire leg. If used on only one shoe, this will increase the overall leg length compared to the opposing side. The effect would be that of a leg length discrepancy just as it is with adding an external device to the shoe's native outsole in the prior category. The result will be an awkward gait, a pelvic shift, and undo stress or discomfort over time referred to the hip and spine. In situations where inserts cover the shoe's entire native insole, they must be cut and adjusted in accordance with the size of the wearer's foot, the size of the shoe's native insole over which they will be placed, and the amount of available interior shoe space. If the type of inserts that is being used does not cover the shoe's entire native insole, they must either sit freely inside the shoe or be adhered to the inside of the shoe. This makes position placement and maintenance of that position very problematic as well.
With both types of inserts, those that cover the shoe's entire native insole and those that do not, they frequently tend to slide around changing positions within the shoes. This causes the burdensome and continual need for the inserts to be repositioned or replaced. In general when using any inserts, the need for sizing, placement, positioning, and maintenance is very cumbersome and time consuming. Their use will usually require much trial and error and adjustments. Although inserts can be made somewhat universal to the shoe, it's only after this tedious modification by the patient or healthcare provider. More importantly however are the potential risks associated with their use. By raising the height of the foot from the ground as it sits on the added insert, this too, as with the first category, changes the center of gravity and stability of the shoe potentially leading to balance issues, falls, and foot, ankle or other injury. Furthermore, any insert, being foreign to a prefabricated shoe that makes direct contact with a wearer's foot can cause pressure points, friction blisters, or skin breakdown. This is particularly dangerous to wearer's who have healing or vascular compromise, or peripheral neuropathy due to Diabetes Mellitus, Peripheral Vascular Disease, or immuno-compromise. These persons are at a much higher risk for developments of skin ulcerations leading to severe infections that can lead to a need for amputations. If the inserts are cut or sized inappropriately, this can increase these risks and cause further discomfort by uneven contours, and pressure points against the foot inside the shoe.
In the third category, those that might chemically engineer the soles in their fabrication to have a variability of durometry or hardness, also have a host of problems. Although the fit and feel of the shoe may not be grossly affected, it greatly affects the overall durability and performance of the shoe. By changing the chemical makeup of the sole itself in this way, although a wedge effect may occur after weight and pressure is applied causing it to compress more on the softer portion, this changes the wear ability of the shoe and the tread. The softer less firm side will wear out much faster, and the harder firmer side by default will wear out more slowly. So ultimately uneven tread wear increased on the softer side of the sole will cause the wedge effect to increase and not remain constant or therapeutic. This causes the desired corrective measure to become less effective and can potentially cause knee, foot, and ankle pain to increase proportionally as the angle increases out of the desired therapeutic range. Moreover, as the shoes wear out quickly, they would need to be replaced, adding unnecessary cost to the therapeutic process.
These shoes would likely be more expensive than the normal shoe also because of the complex chemical engineering that must be used during fabrication. For that matter, if any of the other two categories were custom made to the individual, the cost would rise significantly as well. Most importantly however with this third category are the risks and dangers to the wearer associated with the varying sole hardness and the uneven tread wear. Firstly, during normal ambulation, stability of gait is determined greatly by the expected plantar of equal durometry against the bottom of the foot transferred to the ankle medial to lateral. By having unequal durometry with one side of the sole more or less firm than the other side, this creates a problem for the foot and ankle to compensate especially during ambulation over uneven surfaces. This can lead to foot and ankle injury, or even falls resulting in further more serious injury. Furthermore, the durometry and wear-ability directly affects the grip and traction of the shoe's outsoles. The softer side will have much more grip and traction prior to it wearing out, but decreased wear-ability by default. The harder firmer side, although having greater wearability, by default will have less grip and traction. This can potentially cause loss of traction thereof during ambulation resulting in a fall or serious injury. It is a fact that there is a great population of people with many ailments, particularly involving the knees. As stated, the patents mentioned above, and other prior-art, although they make an attempt, fail to adequately solve the problems associated with painful or arthritic knees and in many cases add additional problems or risks to the equation by their design.
In the fourth category, those that wedge only a portion of the sole, or have an additional heel to toe taper cause problematic issues as well. As noted in the above prior art if the lateral wedge is limited to a portion of the sole, like the forefoot only, for example, then not only does it limit its application to only 5% of the population with a specific foot deformity, but it also creates a significant localized pressure point on the lateral forefoot. Having an unequal localized pressure point can cause skin breakdown on the foot and discomfort. It is particularly risky to use with any patient who may have lower extremity peripheral neuropathy (decreased sensory perception in the feet). If the lateral wedge is limited to the heel and forefoot then the same risks applies above with regards to the pressure points and discomfort, but this also puts a significant amount of stress on the unsupported base and shaft of the 4th and 5th metatarsals (the bones proximal to the small toes that could lead to stress fractures. Lastly, a lateral wedge that traverses the span on the lateral side but simultaneously is tapering down from the heel to toes (like a prior art that is similar to a heel lift), causes problems as well and is self-defeating by limiting the load transfer. Additionally these double or multidirectional bevel particularly the longitudinal bevel causes a progressively decreasing and varying lateral wedge angle moving from the back of the lateral compensation to the front of the lateral compensation. This type of wedge puts significant stress localized on the anterolateral ankle, and also causes a forced rotation of the lower extremity. Furthermore it causes unequal torque of the foot and doesn't adequately transfer the load uniformly away from the medial knee joint compartment across the anterior and posterior horns. The solution to equal load transfer away from the entire medial knee compartment can be demonstrated by walking barefoot (or with normal uncompensated footwear) and parallel with each respective foot on a ground surface that has a lateral incline. If both feet are walking each parallel on a lateral inclined surface if the angle is steep enough it will feel as if the person is walking with the knees in more of a valgus (knock knee) gait. Although a steep angle would be an extreme example for demonstrative purposes only, this essentially is the hallmark of the preferred embodiment of the present invention. To a much less lateral degree angle of course (almost unperceivable) but equally unloading the entire medial knee joint compartment front to back by fully supporting the lateral feet from heel, midfoot, forefoot and toe combined at the same height or thickness on the lateral side from back to front with a constant lateral wedge angle spanning the entire lateral side longitudinally from back to front. This of course is distinctly different than the aforementioned prior art that have a varying and/or decreasing lateral wedge angle from back to front.
Therefore, there is a great need for a safe, effective, and universal orthopedic adjustment that is integrated into the construction and design of the shoe sole itself, whereby the shoe fits comfortably without altering its performance. The lateral wedge angle must traverse the entire longitudinal span of the lateral side at a uniformed equal thickness from front to back. The effect would be, as mentioned above, that of someone walking parallel to and on a laterally inclined walking surface (with respect to each foot with or without shoes). This effect, while allowing the foot to be at neutral 90 degree longitudinal angle with respect to the lower leg when standing, pitches each foot and ankle uniformly from back to front into a valgus (lateral wedged angle) position while supporting the entire lateral feet (heel, midfoot, forefoot, and toes) at a constant thickness simultaneously front to back. This then allows for no localized stress or pressure points on the feet or ankles while uniformly transferring the load off the medial knee joint compartment front to back throughout the entire contacted ambulatory range. The present invention solves all these problems and more. It combines or encompasses all the benefits of the prior-art, it enhances and improves the all the benefits of the prior art, but has none of the detriments or drawbacks of the prior-art.